DDE A0001409678 | Genuine Freightliner® DEF Pump, Exchange Supply Unit

Description: A DEF Pump / Exchange Supply Unit DDE A0001409678 is part of a Diesel Exhaust Fluid (DEF) system used on modern diesel vehicles and equipment. DEF is a liquid (mostly purified water + urea) used to reduce harmful emissions. It’s injected into the exhaust system to help clean exhaust gases using SCR (Selective Catalytic Reduction) technology. Part Number: DDE A0001409678 Condition: New Manufacture/Brand: Freightliner Fits DDE A0001409678 For Mercedes-Benz, Freightliner, Detroit Diesel DD13/DD15 Purpose of using DDE A0001409678: 1. Delivers DEF to clean exhaust gases The DEF pump moves Diesel Exhaust Fluid from the DEF tank to the exhaust system. DEF is injected into the exhaust to break down harmful nitrogen oxides (NOx) into safer gases (nitrogen and water vapor). 2. Controls the correct amount and pressure The supply unit makes sure DEF is delivered at the right pressure and quantity. This prevents: Too much DEF (which can damage components) Too little DEF (which causes emission failures and warning lights) 3. Keeps the vehicle legal and operational Proper DEF delivery helps the vehicle meet emissions regulations. If the DEF pump fails, many vehicles will: Show DEF or check engine warnings Reduce engine power Eventually limit or prevent engine starting 4. Why use an Exchange Supply Unit specifically It replaces a failed pump with a remanufactured, tested unit. It’s: Faster to install than repairing parts More affordable than buying new Designed to restore full system function Signs of a Bad DEF Pump DDE A0001409678: Warning lights & messages DEF / SCR warning light comes on Check Engine Light Messages like: “DEF system fault” “Service DEF system” “Emissions system problem” “No engine restart in ___ miles” Engine performance issues Reduced engine power (limp mode) Engine speed or vehicle speed may be limited In some cases, the vehicle won’t start after a countdown DEF-related problems DEF level doesn’t change even after driving DEF consumption is abnormal (using too much or none at all) Crystallized DEF around the pump or lines (white powder) DEF leaks under the vehicle Noises or pump behavior No priming sound from the DEF pump when the key is turned on Clicking, buzzing, or whining noises from the DEF pump area Diagnostic trouble codes (examples) Codes related to DEF pressure, flow, or pump control SCR efficiency or NOx sensor faults caused by poor DEF delivery Cold-weather symptoms DEF system fails to build pressure after startup Longer warm-up times before warnings clear About the Manufacturer – Freightliner: Freightliner is a major American truck manufacturer known for producing reliable, heavy-duty commercial vehicles. Founded in 1942 and now part of Daimler Truck North America, Freightliner builds semi-trucks, vocational trucks, and specialized vehicles widely used in freight transport, construction, and logistics. The brand is recognized for durability, advanced engineering, fuel efficiency, and strong support through a large service and dealer network.